There are things that a contract cannot properly require a party to do, such as committing crimes or pleading not guilty. I think also you can't have a contract that requires someone not to vote.
But copyright licenses are not contracts, and there are many licenses that are revocable, and are automatically revoked under certain conditions.
Can a copyright license require doing, or punish (via revocation) not doing, things that a contract could not?
For example, can I license a piece of software only to people who do not vote, by saying that the license is revoked automatically if a person votes? Can I license a short story to be freely copied and read by anyone, on the condition that they never plead guilty to a crime? Or, can I license people to download and view copies of a short film, only on the condition that they do not exercise their right to use excerpts of the work for criticism or parody under fair use?
If I can't get a license like this to "work", do the people I distribute copies to end up with a more permissive license without the unenforceable terms? Or do they end up with no license at all?
